Synthetic firelog and method for making same

ABSTRACT

A synthetic firelog is made from substantially 100% leaves mixed with a binder. Preferably, the synthetic firelog is comprised of a base material that is substantially 100% tree leaves. The leaves may be from any of a variety of trees, including, but not limited to, oak, maple, poplar, or birch trees, or mixtures thereof. Most preferably, the leaves consist primarily of oak tree leaves. However, it will be appreciated that numerous varieties of tree leaves, and mixtures thereof, may be used. The binder is a wax material, preferably paraffin wax. A method for making the synthetic firelog is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/850,566, entitled “Leaf Log and Method ofProducing the Same,” filed on Oct. 10, 2006.

BACKGROUND OF THE INVENTION

The present invention relates generally to a synthetic firelog made fromwaste organic matter. More particularly, the present invention relatesto a synthetic firelog, and a method for making same, comprised ofsubstantially 100% tree leaves mixed with a binder.

Synthetic firelogs are well known in the prior art and have been soldcommercially for years. The earliest synthetic firelogs were comprisedof a sawdust base material mixed with a binder, such as wax. However,numerous sawdust substitutes have been used over the years, andsynthetic firelogs made from various cellulosic materials, such as woodpulp, paper, cardboard and the like (often obtained as by-products orresidues from industrial or agricultural operations) mixed with a waxbinder, have been developed.

For example, U.S. Pat. No. 3,297,419 describes the use of rice hulls orshredded paper. U.S. Pat. Nos. 3,843,336 and 3,880,611 disclose the useof reclaimed pulp and Northern Kraft paper beater stock, respectively.U.S. Pat. No. 4,040,796 teaches firelogs composed of ground bark andpeanut shells. U.S. Pat. No. 4,043,765 describes firelogs comprises ofcrushed nut shells, straw, paper pulp, and cotton waste, and U.S. Pat.No. 4,120,666 discloses the use of shredded newsprint.

Other synthetic firelog compositions include: sawdust splinters, cottonlinter and charcoal powder, as taught by U.S. Pat. No. 4,302,210;bagasse, chopped straw, waste paper in pulp, shredded or flaked form,sphagnum moss, nut shells, coffee grounds, fibrous residue left afterfruit or vegetable juice extraction, cotton waste and bark, disclosed inU.S. Pat. No. 4,326,854; and, green sawdust, coal liquid, and sorghum,described in U.S. Pat. No. 4,333,738.

Additionally, some prior art synthetic firelogs use combinations ofvarious yard waste, such as tree branches, grass and leaves, mixed witha binder. Such synthetic firelogs, and methods of producing thefirelogs, are described in U.S. Pat. Nos. 4,102,653; 4,326,854;4,333,738; 6,136,054; 5,393,310; and, 6,719,816. Formation of suchsynthetic firelogs, as discussed in the preceding patents, typicallyinvolves mixing various cellulosic materials at prescribed percentages,adding a heated (melted) binder material, mixing the binder materialwith the cellulosic materials, compressing the mixture into acylindrical mold to form a generally log-shaped structure and allowingthe mixture to cool.

Optionally, chemicals that impart specific scents, aromas or sounds(such as crackling) to the synthetic firelogs may be added, such asthose disclosed by U.S. Pat. Nos. 6,602,306 and 4,818,249.

While numerous materials and combinations of materials have been used inthe prior art as the base materials for synthetic firelogs, to theapplicants' knowledge, the prior art has not developed a syntheticfirelog comprised of substantially 100% tree leaves as a base material.The closest analogous prior art is U.S. Pat. No. 5,393,310 issued toWollen, identified above.

The Wollen patent discloses a method for making an artificial fireplacelog comprising the steps of mixing grass clippings and leaves takendirectly from a lawn without further processing, in an amount from 60%to 80%, by weight, of the total weight of all materials, with wood chipsand sawdust in an amount from 10% to 15%, by weight of the total weightof all materials. The grass clippings and leaves mixture preferablycomprises 50% grass clippings and 50% leaves. A binder material is addedin an amount in the range of 5% to 10%. The binder material is selectedfrom a group consisting of resin glues and waxes in liquid.

The Wollen patent teaches a mixture of grass clippings, leaves, woodchips and sawdust as the base material for its artificial fireplace log.As Wollen notes, such a composition may be useful in light of the manycommunities that require residential property owners retain all yardwaste, including grass clippings, leaves, and twigs, and either compostthem, or ship them to a central composting location.

However, it would be even more useful and beneficial if the basematerial for a synthetic firelog was comprised of substantially 100%tree leaves. First, tree leaves are a renewable resource that areavailable in abundance. Lawns and forests provide an ample supply ofleaves that otherwise would be undesirably deposited in landfills orburned outdoors. Additionally, creating a synthetic firelog from leavespreserves the trees themselves. Thus, the trees may continue to producenew leaves season after season while deforestation is desirably reduced.Lastly, forming a synthetic firelog of a base material comprised ofsubstantially 100% tree leaves, without the inclusion of significantamounts of other yard waste or sawdust, would simplify the manufacturingprocess, reduce costs and create a firelog having a more uniform andpredictable burn.

Accordingly, there is a need for a synthetic firelog formed from a basematerial comprised of substantially 100% tree leaves. Desirably, thesynthetic firelog is comprised of substantially 100% tree leaves mixedwith a paraffin wax binder. More desirably, the synthetic firelogproduces a uniform and predictable burn. Most desirably, the syntheticfirelog may be formed in a variety of diameters and lengths so thefirelog may be used in numerous applications, such as fireplaces, firepits, wood burning stoves, pellet burning stoves and the like.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a synthetic firelog made fromsubstantially 100% tree leaves along with a binder, and a method ofmaking same. The synthetic firelog is comprised of a base material thatis substantially 100% tree leaves. The leaves may be from any of avariety of trees, including, but not limited to, oak, maple, poplar, orbirch trees, or mixtures thereof. The binder is a wax material,preferably paraffin wax.

The synthetic firelog preferably is comprised of about 50%, by volume,leaves and 50%, by volume, binder, although other leaf/bindercompositions are possible depending upon the desired burn time and theshape and size of the firelog. The synthetic firelog may be formed inany number of shapes and sizes, but a typical synthetic firelog isformed in a generally cylindrical shape about 14 inches long and about 4inches in diameter. Other lengths, diameters and shapes are possible,including pellets, depending on the desired use and burn time. In someembodiments, the synthetic firelog of the present invention may includeadditives to create a desired scent or aroma when the firelog is burned.

A method for making synthetic firelog of the present invention includesthe steps shredding a quantity of dried leaves, mixing with a quantityof liquid binder until the binder coats the mixture, compressing themixture in a mold to form a compacted mass, extruding the compacted massin the desired shape and with the desired dimensions and allowing theextruded compacted mass to cool and harden.

These and other features and advantages of the present invention will beapparent from the following detailed description, in conjunction withthe appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The benefits and advantages of the present invention will become morereadily apparent to those of ordinary skill in the relevant art afterreviewing the following detailed description and accompanying drawings,wherein:

FIG. 1 is perspective view of the synthetic firelog of the presentinvention;

FIG. 2 is a block diagram of the various steps in a method for makingthe synthetic firelog of the present invention;

FIG. 3 is a sectional view of the screw extruder employed in the processof the making the synthetic firelog of the present invention; and,

FIG. 4 is a sectional view of the piston chamber employed in the processof making the synthetic firelog of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is susceptible of embodiment in variousforms, there is shown in the drawings and will hereinafter be describeda presently preferred embodiment with the understanding that the presentdisclosure is to be considered an exemplification of the invention andis not intended to limit the invention to the specific embodimentillustrated.

It should be further understood that the title of this section of thisspecification, namely, “Detailed Description of the Invention,” relatesto a requirement of the United States Patent Office, and does not imply,nor should be inferred to limit the subject matter disclosed herein.

Referring now to the drawings, in which similar or corresponding partsare identified with the same reference numeral, and more particularly toFIG. 1, there is shown a synthetic firelog 1 made in accordance with thepresent invention.

Synthetic firelog 1 is comprised of substantially 100% tree leaves as abase material, mixed with a binder. The leaves may be from any of avariety of trees, including, but not limited to, oak, maple, poplar, orbirch trees, or mixtures thereof. Preferably, the binder consists of aparaffin wax.

It has been found that oak leaves, in particular, are quite suitable foruse as a base material for synthetic firelog 1 of the present inventionsince oak leaves tend to be dryer, or tend to dry faster, than othertree leaves. However, it will be appreciated that many different typesof tree leaves are suitable for use as the base material of syntheticfirelog 1 of the present invention, and all such tree leaves, andmixtures thereof, are included within the scope of this disclosure.

As those skilled in the art will recognize, negligible amounts of grass,sticks or other organic yard waste or natural materials may be presentin the base material depending on the source of the leaves. For example,leaves collected from municipalities that have been raked fromhomeowners' lawns and city properties may contain small amounts of otheryard waste (dead grass, twigs, etc.), while leaves collected from aforest floor may contain small amounts of other organic materials(seeds, twigs, etc.). However, the amounts of these non-leaf materialstypically are negligible and have no significant effect on theperformance or qualities of synthetic firelog 1.

Along those lines, it will be recognized that, while paraffin wax is thepreferred binder for synthetic firelog 1, other types of wax, such asrefined wax, petroleum wax and commercial wax, may also be utilized bothas a binder and to provide fuel for the continual burning of thefirelog.

In the preferred embodiment, synthetic firelog 1 is comprised of amixture of approximately 50%, by volume, shredded tree leaves as a basematerial and approximately 50%, by volume, paraffin wax as a binder andcombustion controller. The tree leaves preferably are shredded to a sizeof approximately 1 to 3 inches. This may be done using a shredder ormulcher as is known in the art and as is commonly used for lawnmaintenance.

It has been found that this composition results in a synthetic fireloghaving an attractive appearance, an attractive flame while burning and asufficiently long burn time.

For example, using the preceding composition, a sample synthetic firelogmade according to the principles of the present invention was formed ina generally cylindrical shape, having a length of about 14 inches and adiameter of about 4 inches. The firelog weighed approximately 3 pounds,yielding a density of about 30 pounds per cubic foot. The sample logdesirably burned for approximately 2 hours and produced an aestheticallyattractive flame.

However, those skilled in the art will recognize that various shapes,dimensions, compositions and densities of synthetic firelog 1 arepossible without departing from the scope of the present invention.

For example, while synthetic firelog 1 preferably is generallycylindrical in shape and is formed to mimic the size and appearance of atraditional wood firelog, other shapes, such as rectangular or box-likeshapes, are possible if needed for specific uses. Similarly, while a 14inch length and a 4 inch diameter are fairly standard dimensions forprior art artificial firelogs, synthetic firelog 1 may be formed innumerous other lengths and diameters as dictated by the desired use andburn time.

Along those lines, synthetic firelog 1 may also be formed as a pellet,having a relatively small length (approximately ½ inch) and a smalldiameter (approximately ¼ to ½ inch). As a pellet, the synthetic firelogof the present invention may be used in pellet stoves, central heatingfurnaces and other heating appliances that use pelletized fuel.

The pellets may be formed by the methods disclosed in the instantapplication, by cutting larger synthetic firelogs formed according tothe present invention or by other pellet formation means as are known tothose skilled in the art. When the synthetic firelog of the presentinvention is to be formed as a pellet, it will be appreciated that thetree leaves used as the base material must be shredded to a smaller sizethan previously described herein, perhaps on the order of about 1/16inch to ⅛ inch, or smaller.

Additionally, it may be desirable to increase or decrease the desiredburn time by increasing or decreasing the amount of paraffin wax binderin the composition of synthetic firelog 1, or by substituting adifferent wax binder for the preferred paraffin wax binder. Therefore,the density of synthetic firelog 1 of the present invention may vary andmay preferably range from about 10 pounds per square foot (or lower) toabout 40 pounds per square foot (or higher).

In some embodiments, synthetic firelog 1 may also include additives tocreate a desired scent or aroma when the firelog is burned. Suchadditives are well known to those skilled in the art.

All such variations in the shape, dimensions and composition ofsynthetic firelog 1 are included within the scope of the presentdisclosure.

As shown in FIG. 2, the preferred method to manufacture of syntheticfirelog 1 of the present invention comprises five primary steps,including shredding a collection of dried leaves, mixing with a liquidbinder until the binder coats the mixture, compressing the mixture in amold to form a compacted mass, extruding the compacted mass in thedesired shape and with the desired dimensions and allowing the extrudedcompacted mass to cool and harden.

First, a collection of dried leaves is shred to a desired size. Asdiscussed above, the leaves may be from any of a variety of trees,including, but not limited to, oak, maple, poplar, or birch trees, ormixtures thereof. Most preferably, the leaves consist primarily of oaktree leaves. However, it will be appreciated that numerous varieties oftree leaves, and mixtures thereof, may be used.

The leaves may be obtained from various sources, such as frommunicipalities that collect leaves from residential properties or fromforests. As noted above, negligible amounts of grass, sticks or otherorganic yard waste or natural materials may be mixed in with the leavesdepending on the source of the leaves. However, the amounts of thesenon-leaf materials typically are negligible and have no significanteffect on the performance or qualities of the synthetic firelog of thepresent invention.

If the leaves are wet, the leaves preferably are dried using techniquesknown to those skilled in the art, such as by spreading them out underthe sun or by passing air through the leaves as they are stored in astorage vessel. However, the leaves preferably should not be so dry thatthey crumble into very fine dust particles when handled.

The collection of dried leaves is then passed through a shredder device.Any number of shredders or mulchers as are known in the art and as arecommonly used for lawn maintenance may be used. The tree leavespreferably are shredded to a size of approximately 1 to 3 inches (asnoted above, for creating a pelletized synthetic firelog, the leavesshould be shredded to a smaller size).

A predetermined quantity of dried, shredded leaves is then mixed with aheated liquid binder until the binder coats the mixture. The mixture iscompressed in a mold to form a compacted mass. The compacted mass isthen extruded in the desired shape and dimensions and allowed to cooland harden, thereby forming the synthetic firelog of the presentinvention.

In one embodiment, the method for forming a synthetic firelog accordingto the principles of the present invention can be accomplished using ascrew press 10 as shown in FIG. 3.

A predetermined quantity of shredded dry leaves 11 is fed into a hopper12 where the leaves are introduced into a screw chamber 13. Apredetermined quantity of paraffin wax is heated using a heater (notshown) to temperature suitable to liquefy the wax (typically 120-160degrees Fahrenheit) and is added to screw chamber 13 through port 14. Inthe preferred embodiment, the quantity of wax is approximately equal tothe quantity of leaves, as discussed above.

Leaves 11 are mixed with the wax in screw chamber 13 such that the waxcoats leaves 11. This is accomplished by means of a flighted screwelement 15 affixed on a rotating shaft 16. Shaft 16 is driven by a motor17 that causes shaft 16 to rotate and screw element 15 to mix leaves 11and the wax and to advance the mixture through screw chamber 13. The endof screw chamber 13 is tapered (shown at 19) and formed with an opening19 through which the compressed mixture 20 is extruded.

Compressed mixture 20 is then allowed to cool and harden, after which ismay be cut to the desired length to form the synthetic firelog.

In a second embodiment, the method for forming a synthetic firelogaccording to the principles of the present invention can be accomplishedusing a piston press 30 as shown in FIG. 3.

In this embodiment, a predetermined quantity of shredded dry leaves ismixed with a predetermined quantity of melted paraffin wax. In thepreferred embodiment, the quantity of wax is approximately equal to thequantity of leaves, as discussed above.

The mixture of leaves and wax is introduced into a chamber 32 and apiston 33 is used to compress the mixture in chamber 32 to form acompressed mixture 31. Compressed mixture 31 may then be ejected fromchamber 32 and permitted to cool and harden, after which is may be cutto the desired length, if necessary, to form the synthetic firelog.

All patents referred to herein, are hereby incorporated herein byreference, whether or not specifically done so within the text of thisdisclosure.

In the present disclosure, the words “a” or “an” are to be taken toinclude both the singular and the plural. Conversely, any reference toplural items shall, where appropriate, include the singular.

From the foregoing it will be observed that numerous modifications andvariations can be effectuated without departing from the true spirit andscope of the novel concepts of the present invention. It is to beunderstood that no limitation with respect to the specific embodimentsillustrated is intended or should be inferred. The disclosure isintended to cover by the appended claims all such modifications as fallwithin the scope of the claims.

1. A synthetic firelog comprising: a base material; and a binder;wherein the base material is comprised of substantially 100% treeleaves, and wherein the binder is comprised of a wax.
 2. The syntheticfirelog of claim 1 wherein the tree leaves are shredded.
 3. Thesynthetic firelog of claim 2 wherein the tree leaves are shredded to asize of about 1 to 3 inches.
 4. The synthetic firelog of claim 1 whereinthe tree leaves are selected from a group consisting of oak leaves,maple leaves, poplar leaves, birch leaves and mixtures thereof.
 5. Thesynthetic firelog of claim 1 wherein the wax is a paraffin wax.
 6. Thesynthetic firelog of claim 1 wherein the wax is selected from a groupconsisting of paraffin wax, refined wax, petroleum wax and commercialwax.
 7. The synthetic firelog of claim 1 wherein a volume of the basematerial is about equal to a volume of the binder.
 8. The syntheticfirelog of claim 1 wherein a volume of the base material is differentthan a volume of the binder.
 9. The synthetic firelog of claim 1 whereinthe firelog is formed in a generally cylindrical shape.
 10. Thesynthetic firelog of claim 1 wherein the firelog is formed as a pellet.11. The synthetic firelog of claim 1 wherein the firelog has a densityof about 30 pounds per cubic foot.
 12. The synthetic firelog of claim 1wherein the firelog has a density from between about 10 pounds per cubicfoot to about 40 pounds per cubic foot.
 13. A method for making asynthetic firelog comprising the steps of: shredding a quantity of treeleaves to form a base material comprised of substantially 100% treeleaves; melting a binder; mixing a quantity of the base material with aquantity of the binder to form a mixture; compressing the mixture toform a compacted mass; extruding the compacted mass; and allowing theextruded compacted mass to cool and harden.
 14. The method for making asynthetic firelog of claim 13 wherein the tree leaves are shredded to asize of about 1 to 3 inches.
 15. The method for making a syntheticfirelog of claim 13 wherein the tree leaves are selected from a groupconsisting of oak leaves, maple leaves, poplar leaves, birch leaves andmixtures thereof.
 16. The method for making a synthetic firelog of claim13 wherein the binder is a paraffin wax.
 17. The method for making asynthetic firelog of claim 13 wherein the binder is selected from agroup consisting of paraffin wax, refined wax, petroleum wax andcommercial wax.
 18. The method for making a synthetic firelog of claim13 wherein the quantity of the base material is about equal to thequantity of the binder.
 19. The method for making a synthetic firelog ofclaim 13 wherein the quantity of the base material is different than thequantity of the binder.
 20. The method for making a synthetic firelog ofclaim 13 further comprising the step of cutting the extruded compactedmass to a desired length.